We found 53 dictionaries that define the word numb'er:

General (26 matching dictionaries)

1. number: Longman Dictionary of Contemporary English
2. number: Merriam-Webster
3. number, number: Oxford Learner's Dictionaries
4. number: American Heritage Dictionary of the English Language
5. number: Collins English Dictionary
6. number: Vocabulary.com
7. Number, number, number: Wordnik
8. number: Cambridge Advanced Learner's Dictionary
9. number: Wiktionary
10. number: Webster's New World College Dictionary, 4th Ed.
11. number: Infoplease Dictionary
12. number: Dictionary.com
13. number: Online Etymology Dictionary
14. number: Cambridge Essential American English Dictionary
15. Number (disambiguation), Number (grammar), Number (linguistics), Number (magazine), Number (music), Number (sports), Number, The Number (book): Wikipedia, the Free Encyclopedia
16. Number: Online Plain Text English Dictionary
17. number: Webster's Revised Unabridged, 1913 Edition
18. number: Rhymezone
19. number: AllWords.com Multi-Lingual Dictionary
20. number: Webster's 1828 Dictionary
21. number: FreeDictionary.org
22. number: TheFreeDictionary.com
23. number: Wikimedia Commons US English Pronunciations
24. number: Mnemonic Dictionary

Art (5 matching dictionaries)

25. Number: Glossary of English Grammar Terms
26. The Organon: A Conceptually Indexed Dictionary (by Genus and Differentia) (No longer online)
27. Linguistic Glossary (No longer online)
28. number-: A Cross Reference of Latin and Greek Elements
29. Number: Lexicon of Linguistics

Business (2 matching dictionaries)

30. Bouvier's Law Dictionary 1856 Edition (No longer online)
31. Number (mathematics), number: Legal dictionary

Computing (1 matching dictionary)

32. Number (disambiguation), Number (mathematics), number: Encyclopedia

Medicine (5 matching dictionaries)

33. number: Merriam-Webster Medical Dictionary
34. Dorland's Illustrated Medical Dictionary (No longer online)
35. online medical dictionary (No longer online)
36. number: Medical dictionary
37. Number (mathematics): Medical dictionary

Miscellaneous (3 matching dictionaries)

38. Navajo Code Talkers' Dictionary (No longer online)
39. Encyclopedia of Graphic Symbols (No longer online)
40. number: Idioms

Religion (1 matching dictionary)

41. Number: Smith's Bible Dictionary

Science (3 matching dictionaries)

42. Number: Eric Weisstein's World of Mathematics
43. Number: Eric Weisstein's World of Physics
44. number: PlanetMath Encyclopedia

Slang (5 matching dictionaries)

45. number: Green’s Dictionary of Slang
46. number: English slang and colloquialisms used in the United Kingdom
47. Number: Street Terms: Drugs and the Drug Trade
48. numb'er, number: Urban Dictionary
49. Number: Twists, Slugs and Roscoes: Hardboiled Slang

Tech (2 matching dictionaries)

50. AUTOMOTIVE TERMS (No longer online)
51. National Weather Service Glossary (No longer online)

(Note: See numberable as well.)

Definitions from Wiktionary (numberable) ▸ adjective:  Capable of being numbered or counted. ▸ Also see numberable Similar: numeral, enumerate, count, amount, total, add up, figure, routine, telephone number, phone number, more... Opposite: word, letter, text, phrase, symbol Types: natural number, whole number, integer, rational number, irrational number, real number, complex number, more... Phrases: A Number, large number, small number, number one, phone number, more... Adjectives: large, total, small, great, limited, certain, considerable, average, infinite, whole, sufficient ▸ Word origin ▸ Words similar to numb'er ▸ Usage examples for numb'er ▸ Idioms related to numb'er ▸ Wikipedia articles (New!) ▸ Popular nouns described by numb'er ▸ Words that often appear near numb'er ▸ Rhymes of numb'er ▸ Invented words related to numb'er